Any home improvement project involving plumbing, such as the installation or replacement of a diverter tub spout, can be very intimidating. We are frequently told that plumbing is something that we shouldn't meddle with and that it is something too complicated for a do-it-yourselfer. However, as long as you research how your plumbing works before undertaking your project, there is absolutely no need to call in an expensive plumber.
Step 1 - Choosing a New Tub Spout
You'll need to examine your existing spout and piping in order to know what kind of tub spout you should buy. If necessary, you can skip to Step 2 and remove the existing tub spout first, and then take it to a local home improvement store in order to determine what kind of spout you need to buy. Make sure to take materials into account: for example, plastic valves shouldn't be used in conjunction with copper pipes, and vice versa.
Step 2 - Preparation
Use your putty knife to remove any caulking from around the tub spout. It's important to be very careful here. You don't want your putty knife scratching up your walls or tile.
After removing the caulk, you can unscrew the spout from the screw-threaded end of your pipe that is used to create a seal between the pipe and the spout. This spout is called the 'nipple'. Depending on your plumbing and your personal experience with plumbing, you may have some difficulty unscrewing the spout. If this is the case, you can use a low-viscosity, non-corrosive lubricant such as penetrating oil to loosen it.
Step 3 - Installing the New Spout
Your next action should be to take your Teflon tape and wrap it around the threaded pipe. Don't worry about cutting off the correct length. It is acceptable to use the tape directly off of the roll, and cut when you are satisfied with the coverage. You must be sure that you are covering all of the threads and grooves and that you are not getting any tape on parts that are not threaded. This will prevent your new pipe from leaking.
Once you are finished wrapping the Teflon tape around the nipple, you can screw on your new spout. Be sure that it is secure. If you only screw it on loosely, it will not form a proper seal. When you are finished screwing it on, you can caulk around the base. Be meticulous when caulking. If you're sloppy, it will show and detract from the appearance of your room.
Keep in mind that, although for this kind of job it is acceptable to not call in a professional, there is absolutely nothing wrong with having someone else give advice or perform any (or all!) parts of the installation. Installing the spout yourself is cheaper, less time consuming, and has the added bonus of making you a little bit more aware of how your home functions, but if you feel you cannot handle any part of the process for whatever reason, there is no shame in consulting a professional.